For two decades, western wildfires have grown hotter, burned longer—and become ever more unpredictable. As the climate warms, could big blazes turn into a common hiking hazard?

How it Could Happen

By some estimates, the fire season has increased by 78 days over the
past three decades. “California is experiencing wildland fires every month in areas where, in years past, you couldn’t light a fire with a blowtorch,” says Del Walters, director of Cal Fire, the state forest fire agency. As temperatures increase in the West (0.4 degrees per decade according to the Intergovernmental Panel on Climate Change), mountain snowpack—which acts as nature’s fire retardant when it thaws and cools vegetation—
will diminish. That means bigger, badder wildfires will be “common, and perhaps more common in the next ten years,” says University of California, Merced’s Anthony Westerling, who’s performed one of the most comprehensive analyses of western wildfire trends.